X-ray Crystallographic Studies of pri-miR-21

Conference: 2022: 72nd ACA Annual Meeting
Doug Davies Poster Author
UCB
Bainbridge Island, WA 
 
Thomas Edwards Additional Author
UCB Boston
Bedford, MA 
 
Stephen Mayclin Additional Author
UCB Seattle
Bainbridge Island, WA 
 
Ellen Wallace Additional Author
UCB Seattle
Bainbridge Island, WA 
 
Jessica Williamson Additional Author
UCB Boston
Boston, MA 
 
Madison Weiss Additional Author
UCB Seattle
Bainbridge Island, WA 
 
07/31/2022: 5:30 PM - 7:30 PM
Poster Session 
Portland Marriott Downtown Waterfront 
Room: Exhibit Hall 

Description

Micro RNA (miRNA) are noncoding RNAs that are involved in gene silencing and transcriptional regulation. microRNAs are transcribed as long stem-loop structures (pri-miRNA). These molecules undergo double-stranded cleavage by the enzyme drosha in the nucleus to form a shorter stem-loop called pre-miRNA. After export from the nucleus to the cytoplasm, pre-miRNA undergoes another double-stranded cleavage by the enzyme dicer to eventually form mature miRNA of 20-22 nucleotide residues in length. miR-21 is considered an "onco-miR" because it is one of a family of micro RNAs that are upregulated in some cancers. To understand the structure of miR-21, we performed X-ray crystallography utilizing a general toolkit of RNA binding proteins. Here we describe the structure of nearly full-length pri-miR-21 in complex with an RNA-binding Fab solved at 1.8 Å resolution. All 55 nucleotides of the miR-21 double helical region are visible in the structure including the drosha and dicer cleavage sites. A ligand-bound ternary complex was also captured at 2.0 Å resolution using the tool compound neomycin. Neomycin binds near the dicer cleavage site and distorts the conformation of the RNA backbone near the A29 bulge region.